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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 08/13] x86: add iommu_op to query reserved ranges
This patch adds an iommu_op to allow the domain IOMMU reserved ranges to be
queried by the guest.
NOTE: The number of reserved ranges is determined by system firmware, in
conjunction with Xen command line options, and is expected to be
small. Thus, to avoid over-complicating the code, there is no
pre-emption check within the operation.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
v3:
- Avoid speculation beyond array bounds check.
v2:
- Re-implemented for v2 based on new rangeset.
---
xen/arch/x86/iommu_op.c | 170 ++++++++++++++++++++++++++++++++++++++++--
xen/include/public/iommu_op.h | 39 ++++++++++
xen/include/xlat.lst | 2 +
3 files changed, 205 insertions(+), 6 deletions(-)
diff --git a/xen/arch/x86/iommu_op.c b/xen/arch/x86/iommu_op.c
index 744c0fce27..97811f8ced 100644
--- a/xen/arch/x86/iommu_op.c
+++ b/xen/arch/x86/iommu_op.c
@@ -22,11 +22,70 @@
#include <xen/event.h>
#include <xen/guest_access.h>
#include <xen/hypercall.h>
+#include <xen/nospec.h>
+
+struct get_reserved_ctxt {
+ unsigned int max_entries;
+ unsigned int nr_entries;
+ XEN_GUEST_HANDLE(xen_iommu_reserved_range_t) ranges;
+};
+
+static int get_reserved(unsigned long s, unsigned long e, void *arg)
+{
+ struct get_reserved_ctxt *ctxt = arg;
+
+ if ( ctxt->nr_entries < ctxt->max_entries )
+ {
+ xen_iommu_reserved_range_t range = {
+ .start_bfn = s,
+ .nr_frames = e - s,
+ };
+
+ if ( copy_to_guest_offset(ctxt->ranges, ctxt->nr_entries, &range,
+ 1) )
+ return -EFAULT;
+ }
+
+ ctxt->nr_entries++;
+ return 0;
+}
+
+static int iommu_op_query_reserved(struct xen_iommu_op_query_reserved *op)
+{
+ struct domain *currd = current->domain;
+ struct domain_iommu *iommu = dom_iommu(currd);
+ struct get_reserved_ctxt ctxt = {
+ .max_entries = op->nr_entries,
+ .ranges = op->ranges,
+ };
+ int rc;
+
+ if ( op->pad )
+ return -EINVAL;
+
+ rc = rangeset_report_ranges(iommu->reserved_ranges, 0, ~0ul,
+ get_reserved, &ctxt);
+ if ( rc )
+ return rc;
+
+ /* Pass back the actual number of reserved ranges */
+ op->nr_entries = ctxt.nr_entries;
+
+ if ( !guest_handle_is_null(ctxt.ranges) &&
+ ctxt.nr_entries > ctxt.max_entries )
+ return -ENOBUFS;
+
+ return 0;
+}
static void iommu_op(xen_iommu_op_t *op)
{
switch ( op->op )
{
+ case XEN_IOMMUOP_query_reserved:
+ op->status = iommu_op_query_reserved(&op->u.query_reserved);
+ break;
+
default:
op->status = -EOPNOTSUPP;
break;
@@ -35,13 +94,20 @@ static void iommu_op(xen_iommu_op_t *op)
int do_one_iommu_op(xen_iommu_op_buf_t *buf)
{
- xen_iommu_op_t op;
+ xen_iommu_op_t op = {};
+ size_t offset;
+ static const size_t op_size[] = {
+ [XEN_IOMMUOP_query_reserved] = sizeof(struct
xen_iommu_op_query_reserved),
+ };
+ size_t size;
int rc;
- if ( buf->size < sizeof(op) )
+ offset = offsetof(struct xen_iommu_op, u);
+
+ if ( buf->size < offset )
return -EFAULT;
- if ( copy_from_guest((void *)&op, buf->h, sizeof(op)) )
+ if ( copy_from_guest((void *)&op, buf->h, offset) )
return -EFAULT;
if ( op.pad )
@@ -51,6 +117,16 @@ int do_one_iommu_op(xen_iommu_op_buf_t *buf)
if ( rc )
return rc;
+ if ( op.op >= ARRAY_SIZE(op_size) )
+ return -EOPNOTSUPP;
+
+ size = op_size[array_index_nospec(op.op, ARRAY_SIZE(op_size))];
+ if ( buf->size < offset + size )
+ return -EFAULT;
+
+ if ( copy_from_guest_offset((void *)&op.u, buf->h, offset, size) )
+ return -EFAULT;
+
iommu_op(&op);
if ( __copy_field_to_guest(guest_handle_cast(buf->h, xen_iommu_op_t),
@@ -102,14 +178,23 @@ long do_iommu_op(unsigned int nr_bufs,
int compat_one_iommu_op(compat_iommu_op_buf_t *buf)
{
- compat_iommu_op_t cmp;
+ compat_iommu_op_t cmp = {};
+ size_t offset;
+ static const size_t op_size[] = {
+ [XEN_IOMMUOP_query_reserved] = sizeof(struct
compat_iommu_op_query_reserved),
+ };
+ size_t size;
xen_iommu_op_t nat;
+ unsigned int u;
+ int32_t status;
int rc;
- if ( buf->size < sizeof(cmp) )
+ offset = offsetof(struct compat_iommu_op, u);
+
+ if ( buf->size < offset )
return -EFAULT;
- if ( copy_from_compat((void *)&cmp, buf->h, sizeof(cmp)) )
+ if ( copy_from_compat((void *)&cmp, buf->h, offset) )
return -EFAULT;
if ( cmp.pad )
@@ -119,12 +204,85 @@ int compat_one_iommu_op(compat_iommu_op_buf_t *buf)
if ( rc )
return rc;
+ if ( cmp.op >= ARRAY_SIZE(op_size) )
+ return -EOPNOTSUPP;
+
+ size = op_size[array_index_nospec(cmp.op, ARRAY_SIZE(op_size))];
+ if ( buf->size < offset + size )
+ return -EFAULT;
+
+ if ( copy_from_compat_offset((void *)&cmp.u, buf->h, offset, size) )
+ return -EFAULT;
+
+ /*
+ * The xlat magic doesn't quite know how to handle the union so
+ * we need to fix things up here.
+ */
+#define XLAT_iommu_op_u_query_reserved XEN_IOMMUOP_query_reserved
+ u = cmp.op;
+
+#define XLAT_iommu_op_query_reserved_HNDL_ranges(_d_, _s_) \
+ do \
+ { \
+ if ( !compat_handle_is_null((_s_)->ranges) ) \
+ { \
+ unsigned int *nr_entries = COMPAT_ARG_XLAT_VIRT_BASE; \
+ xen_iommu_reserved_range_t *ranges = \
+ (void *)(nr_entries + 1); \
+ \
+ if ( sizeof(*nr_entries) + \
+ (sizeof(*ranges) * (_s_)->nr_entries) > \
+ COMPAT_ARG_XLAT_SIZE ) \
+ return -E2BIG; \
+ \
+ *nr_entries = (_s_)->nr_entries; \
+ set_xen_guest_handle((_d_)->ranges, ranges); \
+ } \
+ else \
+ set_xen_guest_handle((_d_)->ranges, NULL); \
+ } while (false)
+
XLAT_iommu_op(&nat, &cmp);
+#undef XLAT_iommu_op_query_reserved_HNDL_ranges
+
iommu_op(&nat);
+ status = nat.status;
+
+#define XLAT_iommu_op_query_reserved_HNDL_ranges(_d_, _s_) \
+ do \
+ { \
+ if ( !compat_handle_is_null((_d_)->ranges) ) \
+ { \
+ unsigned int *nr_entries = COMPAT_ARG_XLAT_VIRT_BASE; \
+ xen_iommu_reserved_range_t *ranges = \
+ (void *)(nr_entries + 1); \
+ unsigned int j; \
+ \
+ for ( j = 0; \
+ j < min_t(unsigned int, (_d_)->nr_entries, \
+ *nr_entries); \
+ j++ ) \
+ { \
+ compat_iommu_reserved_range_t range; \
+ \
+ XLAT_iommu_reserved_range(&range, &ranges[j]); \
+ \
+ if ( __copy_to_compat_offset((_d_)->ranges, j, \
+ &range, 1) ) \
+ status = -EFAULT; \
+ } \
+ } \
+ } while (false)
+
XLAT_iommu_op(&cmp, &nat);
+ /* status will have been modified if __copy_to_compat_offset() failed */
+ cmp.status = status;
+
+#undef XLAT_iommu_op_query_reserved_HNDL_ranges
+
if ( __copy_field_to_compat(compat_handle_cast(buf->h,
compat_iommu_op_t),
&cmp, status) )
diff --git a/xen/include/public/iommu_op.h b/xen/include/public/iommu_op.h
index c3b68f665a..02213c12a4 100644
--- a/xen/include/public/iommu_op.h
+++ b/xen/include/public/iommu_op.h
@@ -25,11 +25,50 @@
#include "xen.h"
+typedef unsigned long xen_bfn_t;
+
+/* Structure describing a single range reserved in the IOMMU */
+struct xen_iommu_reserved_range {
+ xen_bfn_t start_bfn;
+ unsigned int nr_frames;
+ unsigned int pad;
+};
+typedef struct xen_iommu_reserved_range xen_iommu_reserved_range_t;
+DEFINE_XEN_GUEST_HANDLE(xen_iommu_reserved_range_t);
+
+/*
+ * XEN_IOMMUOP_query_reserved: Query ranges reserved in the IOMMU.
+ */
+#define XEN_IOMMUOP_query_reserved 1
+
+struct xen_iommu_op_query_reserved {
+ /*
+ * IN/OUT - On entry this is the number of entries available
+ * in the ranges array below.
+ * On exit this is the actual number of reserved ranges.
+ */
+ unsigned int nr_entries;
+ unsigned int pad;
+ /*
+ * OUT - This array is populated with reserved ranges. If it is
+ * not sufficiently large then available entries are populated,
+ * but the op status code will be set to -ENOBUFS.
+ * It is permissable to set this to NULL if nr_entries is also
+ * set to zero. In this case, on exit, nr_entries will still be
+ * set to the actual number of reserved ranges but the status
+ * code will be set to zero.
+ */
+ XEN_GUEST_HANDLE(xen_iommu_reserved_range_t) ranges;
+};
+
struct xen_iommu_op {
uint16_t op; /* op type */
uint16_t pad;
int32_t status; /* op completion status: */
/* 0 for success otherwise, negative errno */
+ union {
+ struct xen_iommu_op_query_reserved query_reserved;
+ } u;
};
typedef struct xen_iommu_op xen_iommu_op_t;
DEFINE_XEN_GUEST_HANDLE(xen_iommu_op_t);
diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
index 3b15c18c4e..93bcf4b4d0 100644
--- a/xen/include/xlat.lst
+++ b/xen/include/xlat.lst
@@ -79,6 +79,8 @@
? vcpu_hvm_x86_64 hvm/hvm_vcpu.h
! iommu_op iommu_op.h
! iommu_op_buf iommu_op.h
+! iommu_op_query_reserved iommu_op.h
+! iommu_reserved_range iommu_op.h
? kexec_exec kexec.h
! kexec_image kexec.h
! kexec_range kexec.h
--
2.11.0
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